A Super-Aged Microminipig Model for the Development of Health Foods for the Elderly: A Pilot Study on the Administration of Sweet Potato Petiole and Leaf Powder

Background/Objectives: To develop an animal model to evaluate efficacy and safety of health foods and drugs in elderly humans, we established the world’s first animal model of super-aged microminipigs (MMPs), aged 8–13 years. Here, we tested a polyphenol-rich bait using this aged preclinical model without sacrificing the animals. Methods: A diet rich in polyphenols, containing sweet potato petioles and leaves, developed by us, was administered long-term, and changes in gut microbiota composition in feces and aging-related cells in the peripheral blood were monitored. Results: Administration of this diet resulted in increased abundance of the genera Muribaculaceae, Oscillibacter, and Desulfovibrio, and a decreased abundance of the genus UCG-002 within the family Oscillospiraceae. By predicting activated or suppressed metabolic enzymes from the percentage of microbiota, 77 enzymes were found to differ significantly after multiple testing corrections before and after sweet potato petiole and leaf administration. KEGG Mapper analysis of these enzymes revealed their involvement in 27 pathways. Flow cytometry analysis of peripheral blood revealed no significant differences in the proportion of ß-galactosidase-positive cells in either group. In contrast, significant increase in the number of Ki-67-positive cells, was observed in some individuals in the treatment group. However, no significant differences in Ki-67 expression were detected after stimulation with anti-CD3/CD28 antibodies. Conclusions: We established a colony of super-aged experimental MMPs to evaluate the efficacy and safety of drugs and health foods in elderly humans. This colony may contribute to such studies in future, with the goal of lifelong maintenance of animals.